A fire at Anglesey Aluminium, one of north Wales' biggest employers, has left production at one-third of normal, the owner has confirmed.
It could be up to three months before full production returns following the blaze on 12 June.
Owner Rio Tinto said a full investigation into the cause of the fire was under way.
About 540 people work at the plant, which produced 148,000 tonnes of hot metal in 2007.
A Rio Tinto spokesman said: "One pot line is running at approximately two-thirds of normal production.
"The second line is not currently operating."
The fire forced the firm to switch off power for four hours to allow firefighters to tackle the blaze and the power cut caused some damage at the two production lines.
Anglesey's smelter uses an electrolytic process requiring large quantities of electricity and with the Wylfa nuclear power plant planned to shut around 2010, the Reuters news agency reported that it was under pressure to secure new power supplies.
"Discussions are continuing and we remain hopeful that a satisfactory outcome can be achieved," the spokesman said.
